1. Field of the Invention
The present invention relates to a library apparatus and, in particular, to a library apparatus for storing a multiplicity of cartridges, having a recording medium built therein, and moving the cartridges to a drive unit by a carriage mechanism thereby to read/write the internal storage media, the library apparatus being adapted to set therein at least a magazine capable of accommodating a plurality of cartridges.
2. Description of the Related Art
With the increase in the amount of information processed by computer systems, a conventional library apparatus comprising cartridge-type storage media (hereinafter referred to simply as cartridges), with magnetic tape built therein, is known as an information storage device for storing a large amount of information. This library apparatus is configured of an access unit for charging and discharging the-cartridges, a drive unit for recording/reproducing data in and from the storage media in the cartridges and an accessor robot (hereinafter referred to simply as the accessor) for moving the cartridges between the access unit and the drive unit.
A conventional ordinary library apparatus has a plurality of internal cells for accommodating a multiplicity of cartridges. Also, this library apparatus is capable of charging from outside or discharging outside a plurality of cartridges at the same time. For this purpose, the library apparatus generally comprises an access unit (hereinafter referred to as a CAS (Cartridge Access Station)) for charging/discharging a magazine accommodating a plurality of the cartridges.
In the process for charging a magazine accommodating a plurality of the cartridges from the CAS into the library apparatus, the first step is for the operator to mount the magazine on the outer periphery of a magazine drum in the access unit from the outside of the apparatus (the operator side of the apparatus). Then, the magazine drum is rotationally driven by a drive motor so that each cartridge accommodated in the magazine is directed inward of the apparatus (toward the space in which the accessor is to move). In discharging the magazine accommodating a plurality of the cartridges by the CAS, on the contrary, the magazine drum is rotationally driven by the drive motor so that the magazine to be discharged is directed outward of the apparatus, and the particular magazine is retrieved by the operator.
In a library apparatus of another type having a rotatable tray outside of the apparatus, a magazine is mounted on a tray tilted toward an external space, after which the tray is returned so that each cartridge accommodated in the magazine is directed inward of the apparatus (toward the space in which the accessor is to move). After that, a pivoted door arranged in the apparatus for separating the interior and the exterior of the apparatus from each other is opened by being rotationally driven by the drive motor, and the magazine is opened inward of the apparatus thereby to charge a plurality of the cartridges. In discharging the magazine from the CAS, on the contrary, the pivoted door is rotationally driven by the drive motor, and after thus separating the magazine from the interior of the apparatus, the tray is rotated and tilted toward the external space. In this way, the magazine is retrieved to discharge the cartridges.
This magazine is provided with a safety stopper mechanism for preventing a plurality of the magazines from jumping out of the magazine in transit. The conventional safety stopper mechanism for the cartridges in the magazine can be one of several types. In one safety stopper mechanism, a lock lever for preventing the cartridges from jumping out is hooked in a notch (depression) formed in each cartridge. Another safety stopper mechanism uses a spring plate to fix the cartridges under pressure.
The CAS for the library apparatuses described above has the following structural problem.
First, in the CAS having a magazine drum, the magazine is mounted in the drum and required to be rotated with the drum at the time of charging/discharging the cartridges. Therefore, there are needed a drive mechanism for rotationally driving the whole drum with the magazines mounted therein and a support structure for rotatably supporting the drum. This poses the problem of a complicated or bulky library apparatus.
Next, in the CAS having a rotatable tray outside of the apparatus, the pivoted door is rotated with the magazine mounted thereon and, therefore, the problem is posed that a space is required to prevent the pivoted door from interfering with the magazine and the cartridges mounted in the magazines. This CAS further requires a space for rotating the tray with the magazine mounted thereon on the one hand and a drive mechanism for rotationally driving the pivoted door, thereby leading to the problem of a complicated and bulky library apparatus.
The two types of CAS described above both use a motor for rotational drive, and therefore the size reduction in the drive mechanism is limited. Also, the need for drive control leads to the problem that the library apparatus becomes bulky and complicated.
The safety stopper mechanism for the cartridges including a lock lever hooked in the cartridges used for the conventional magazine, on the other hand, requires a solenoid and a motor exclusively used for unlocking. This increases the number of parts of the unlocking mechanism and poses the problem of a higher cost and a possible malfunction. In the safety stopper mechanism for cartridges using a spring plate pressed against the cartridges, on the other hand, the spring plate cannot fix the cartridges firmly. In the case where the magazine are shaken or otherwise similarly treated, for example, the cartridges are liable to jump out of the magazine.